Geological evolution of the Hampshire Basin (southern England) during a global climate transition from ‘hothouse’ to ‘coolhouse’ in the Palaeogene

Palaeogene sediments of the Hampshire Basin were a sensitive recorder of fluctuations in climate and eustatic sea level as Earth's climate transitioned from the global early Eocene ‘hothouse’ to the early Oligocene ‘coolhouse’, accompanied by the first permanent continent-scale glaciation of Antarctica at the Eocene/Oligocene boundary. A study of the Palaeogene sediments of the Hampshire Basin is not only interesting from a palaeoclimate perspective, but the marine middle Eocene formations are renowned for containing some of the most abundant and diverse Palaeogene fossil assemblages in the world. In this article, I take you on a tour of the geological evolution of the Hampshire Basin from the end of the Paleocene through to the Pleistocene. I highlight some of the best exposures where sediments can be studied at outcrop and representative fossil assemblages can be collected, along with the economic and archaeological significance of these Palaeogene sediments.     

New data on fauna and stratigraphy of the Semibalki locality,Azov Region

Fauna in the Semibalki locality (Azov Region), its stratigraphic position, and its age were considered. The rocks composing sediments with fossil theriofauna were subject to petrochemical analysis. Taking into account the lithological features of the sediments containing this fauna, it is possible to make the conclusion that the fossil fauna remains are allochthons and their age range is somewhat broader than was considered before.     

Estimation of Natural Radionuclides and Exhalation Rate in Surface Soils of Four Districts of Haryana,India

A fossil wood of Lagerstroemia L. from the Upper Siwalik sediments of Arunachal Pradesh is described. The genus is recorded for the first time from this state. The modern analog of the fossil species i.e. L. tomentosa C. Presl is not found in the fossil locality at present.. The most plausible reason for the disappearance of the species from the fossil locality is an increase in temperature seasonality caused by the upheaval of the Himalaya during the Pleistocene.     

近十五年来蛋化石研究概况

1993年至2008年是中国蛋化石研究不断扩展与深入的时期。这期间的研究更注重于解决盆地地层与蛋化石演化序列间的联系; 开展了翼龙化石胚胎学研究; 通过分子古生物学分析, 尝试了获取古代DNA的方法; 河南西峡恐龙蛋化石博物馆的建立, 成为展示这一阶段进展的突出标志。特别是近几年来, 通过大量资料积累, 发现并揭示出恐龙蛋的变异类型与鸟蛋间的联系, 由此填补了从恐龙到鸟的演化过程中蛋壳形态结构变化的空白。文中还介绍了我国白垩纪几个沉积盆地的生物地层和一些具有特色的蛋化石种类; 提出了新的蛋化石分类意见, 以及与蛋化石有关的生存行为方面的思考。     

Fossil Rotifers and the Early Colonization of an Antarctic Lake

Early Holocene sediments from a continental Antarctic lake (Ace Lake, Vestfold Hills, East Antarctica) contained abundant fossil rotifers of the genus Notholca. The fossil is similar to specimens of Notholca sp. present in modern-day Ace Lake and other fresh and brackish lakes of the Vestfold Hills. Cyanobacteria and protists (chrysophyte cysts, dinoflagellate cysts, and rhizopod tests) were also recovered from the core samples. These sediments were deposited early in the freshwater phase of Ace Lake, soon after deglaciation of the area. The occurrence of this trophically diverse assemblage of organisms at an early stage in the evolution of the lake suggests either that they were part of an endemic Antarctic flora and fauna which pre-dated the last glacial maximum and survived in glacial refugia or that efficient intercontinental dispersal had occurred.     

Hydrocarbons in western North Atlantic surface sediments

High concentrations of hydrocarbons (500–3000 μg/g dry weight) together with a complex and wide molecular weight range of composition, and low ¹⁴C activity of δ¹⁴C = ?833 ± 50%. strongly indicate that fossil fuel hydrocarbons make up the bulk of hydrocarbons in and near the New York Bight dump site areas. The composition and concentrations of hydrocarbons in Hudson Channel sediments suggest some transport of dump site hydrocarbons to areas in the channel midway to the edge of the continental shelf. Sediments at 16 stations in other areas of the continental shelf, continental slope and abyssal plain have hydrocarbon concentrations and compositions indicating that no more than 1 μg/g dry weight of fossil fuel hydrocarbons are present.N-alkanes from land sources were among the most predominant hydrocarbons in all samples except those in the New York Bight region. Their presence in abyssal plain surface sediments documents transport of some land derived organic matter to these deep ocean areas. Two 25-carbon cycloalkenes are among the more predominant hydrocarbons in continental shelf surface sediments except for the dump site areas. These two compounds are present in lower concentrations in slope sediments and are not detected in abyssal plain sediments.     

First report of a dipterocarpaceous fossil wood from Manipur

A fossil wood resembling Shorea and other allied genera of the Dipterocarpaceae is described from the Tipam Group of Manipur. This is for the first time any angiosperm wood is recorded from this state. The fossil collected from Jiribam district is considered as late Miocene in age. Its occurrence indicates warm and humid climate in the region during the deposition of the sediments.     

A fossil coconut fruit from the early Eocene of Gujarat

A fossil fruit resembling extant Cocos nucifera of the family Arecaceae is reported for the first time from the early Eocene sediments of Gujarat. The fossil was collected from the Tarkeshwar lignite mine of the Surat District which belongs to the Cambay Shale Formation. Its occurrence indicates coastal conditions in the region during the depositional period in contrast to arid to semi-arid climate prevailing there at present. The present fossil, along with the previously published palyno-assemblages from the mine supports the equatorial position of the Indian subcontinent at the time of deposition i.e. during the early Eocene.     

New legume fruits from the oligocene sediments of Assam

For the first time a rich assemblage of legume fruits is described from the Late Oligocene sediments of the Makum as well as Dilli-Jeypore coalfields of Assam. A new genus Buteocarpon has been instituted for the fossil fruits resembling Butea Roxb. of the family Fabaceae. In addition, six new species of the genus Leguminocarpon Goeppert are also described. Their presence indicates a warm and humid climate in the region during the deposition of the sediments.     

硅质碎屑岩中的微生物席相关构造——联接现代与过去的纽带

微生物通过自身生命活动可以在硅质碎屑物上形成微生物席.微生物席具有黏结性、柔韧性、抗剥蚀性等特征,与物理营力相互作用可以形成一系列独特的原生沉积构造,即微生物诱发的沉积构造(MISS).形成和保存MISS的基本条件包括经历较低的变质程度、发育于海退—海侵的转折点、出现在有利的“微生物席沉积相”中.微生物席本身很难保存在岩石序列中,所以识别石化MISS具有一定难度.与现代环境中发育的MISS具有相似的几何形态和包含古代微生物席组构是识别石化MISS的有效途径.微生物生长、稳化、障积、捕获和黏结作用可以形成形态各异的MISS,根据这些作用和特征可以将其划分为5大类17小类.对保存在硅质碎屑岩中的微生物诱发的原生沉积构造和现代潮坪中发育的MISS进行综合对比研究,有利于微生物席沉积学的发展,也为进一步理解古代硅质碎屑岩沉积环境提供重要线索.     

<Emphasis Type="Italic">Ficus palaeoracemosa</Emphasis> sp. nov. – A new fossil leaf from the Kasauli Formation of Himachal Pradesh and its palaeoclimatic significance

A new fossil leaf impression is described from the Early Miocene sediments of Kasauli–Kalka road section, Himachal Pradesh. The characteristic leaf venation pattern suggests that it has a close affinity with Ficus L., particularly with F. racemosa L. (= F. glomerata Roxb.). Its presence indicates a warm and humid climate in the region during the deposition of sediments, in contrast to the present day cooler and less humid climate.     

Self-sedimentation of phytoplankton blooms in the geologic record

Understanding the formation of laminated, organic-rich sediments is an essential topic for researchers interested in fossil fuels, biogeochemical cycles, Earth's environmental history and global change. Biologists have very recently demonstrated that some marine phytoplankton blooms actively govern their own sedimentation by the formation of sticky transparent gels that facilitate rapid aggregation, accelerated sinking and efficient export flux. Here we present fossil evidence of unfragmented, low-diversity phytoplankton assemblages preserved as sedimentary laminae and irregular flocs that are attributable to a similar phytoplankton-driven sedimentary mechanism we term ‘self-sedimentation’. The geological evidence suggests that self-sedimentation precludes significant heterotrophic grazing, propels the formation of some conspicuous hemipelagic sedimentary laminae and results in efficient carbon and opal flux to the sediments. We suggest that the self-sedimentation phenomenon may have broad implications for the geological history of biogeochemical cycling, oceanic ecological dynamics, and abrupt atmospheric/environmental change. Broader recognition of the self-sedimentation phenomenon as explicitly defined here is a prerequisite to testing these unconventional hypotheses.     

On the character of Black Sea level rise during the Holocene

The character of changes in the mollusk fauna in the Late Pleistocene and Holocene sediments within the Bulgarian, Northwestern, Crimean, and Kerch segments of the Black Sea shelf has been examined. A bed containing fossil remains of brackish-water and marine mollusks was recognized in these sediments; the bed accumulated, based on results of radiocarbon datings, 500–1000 years ago. The obtained data do not support the existing notion of a catastrophic fill-up of the Black Sea Basin by marine Mediterranean water [19].     

Study of fossil wood from the Middle–Late Miocene sediments of Dhemaji and Lakhimpur districts of Assam,India and its palaeoecological and palaeophytogeographical implications

In order to reconstruct the palaeoclimate, a number of fossil wood pieces were collected and investigated from two new fossil localities situated in the Dhemaji and Lakhimpur districts of Assam. They belong to the Tipam Group considered to be of Middle–Late Miocene in age and show affinities with Gluta (Anacardiaceae), Bischofia (Euphorbiaceae), Bauhinia, Cynometra, Copaifera-Detarium-Sindora, Millettia-Pongamia, and Afzelia-Intsia (Fabaceae). The flora also records a new species of Bauhinia named Bauhinia miocenica sp. nov. The assemblage indicates a warm and humid climate in the region during the deposition of the sediments. The occurrence of some southeast Asian elements in the fossil flora indicates that an exchange of floral elements took place between India and southeast Asia during the Miocene.     

Holocene lake stages and thermokarst dynamics in a discontinuous permafrost affected region,north-eastern Tibetan Plateau

Sediments of a thermokarst system on the north-eastern Tibetan Plateau were studied to infer changes in the lacustrine depositional environment related to climatic changes since the early Holocene. The thermokarst pond with a length of 360 m is situated in a 14.5 × 6 km tectonically unaffected intermontane basin, which is underlain by discontinuous permafrost.A lake sediment core and bankside lacustrine onshore deposits were analysed. Additionally, fossil lake sediments were investigated, which document a former lake-level high stand. The sediments are mainly composed of marls with variable amounts of silt carbonate micrite, and organic matter.On the basis of sedimentological (grain size data), geochemical (XRF), mineralogical (XRD) and micropaleontological data (ostracods and chironomide assemblages) a reconstruction of a paleolake environment was achieved.Lacustrine sediments with endogenic carbonate precipitation suggest a lacustrine environment since at least 19.0 cal ka BP. However, because of relocation and reworking processes in the lake, the sediments did not provide distinct information about the ultimate formation of the lake. The high amount of endogenic carbonate suggests prolonged still-water conditions at about 9.3 cal ka BP. Ostracod shells and chironomid head capsules in fossil lake sediments indicate at least one former lake-level high stand, which were developed between the early and middle Holocene. From the late Holocene the area was possibly characterized by a lake-level decline, documented by a hiatus between lacustrine sediments and a reworked loess or loess-like horizon. After the lake-level decline and the following warming period, the area was affected by thermally-induced subsidence and a re-flooding of the basin because of thawing permafrost.     

Zur Systematik der Kohlenstoff-Schwefel-Eisen-Verhältnisse in Auftriebssedimenten

Abundances of organic carbon, sulfur, and reactive iron in sediments of three upwelling environments (Peru, Oman and Benguela) suggest that organic carbon/reduced sulfur ratios (C/S-ratios) in this category of marine sediments deviate considerably from previously established empirical ratios in normal marine sediments. To clarify the discrepancies, we investigated those components of the diagenetic system that limit the formation of pyrite: sulfate concentrations and reduction rates in pore waters, availability of reactive iron, and the quantity and quality of organic matter. All three limitations are evident in our sample pools. The results suggest that C/S-ratios in recent and fossil marine sediments rich in organic matter may be unsuitable as paleoenvironmental indicators.

     

Implications of trace fossil assemblages from Late Paleozoic Glaciomarine Talchir Formation, Raniganj Basin, India

The trace fossil assemblages of the ice-marginal shallow marine sediments of the Talchir Formation (Permo-Carboniferous), Raniganj Basin, India, record the adverse effect of extreme climatic conditions on biota. The glaciomarine Talchir succession starts with glacial sediments near the base and gradually passes to storm-laid shallow marine sediments up-section. The fine-grained storm sediments host abundant trace fossils. Although the studied ichnites characteristically show marginal marine affinity, the ichnodiversity and bioturbation intensity suggest a lower than normal shallow marine trace fossil population. Further, endobenthic annelids, worms and crustaceans are identified as dominant trace-makers.

Sediment reworking near the ice-grounding line, extremely cold climate, high-energy storm sedimentation and anomalous water chemistry hindered organic colonization during the early phases of Talchir sedimentation. Later, climatic amelioration ushered in a favourable ambience for the benthic community to colonize within or beyond the storm weather wave-base in the outer shoreface–shelf environment. Fluctuating storm energy dominantly controlled the availability and influence of other environmental stimuli in the environment, and thus, governed the distribution, abundance and association of the studied ichnites. However, impoverished ichnodiversity, sporadic distribution of the traces, overall smaller burrow dimensions, absence of body fossils, dominance of worms and annelids as trace-makers all indicate a stressed environmental condition, induced by cold climate and lowered marine salinity due to influx of glacier melt-out freshwater during climatic amelioration, in the Permo-Carboniferous ice-marginal sea.     

A New Fossil Termite(Isoptera,Stolotermitidae,Stolotermes)from the Early Miocene of Otago,New Zealand

<正>The forewing of a termite from Early Miocene lake sediments in Otago,southern New Zealand is figured and described.It exhibits the generic characters of the damp-wood termite Stolotermes Hagen,but differs from forewings of the known species in size and venation pattern and is described as Stolotermes kupe sp.nov.S.kupe represents the first confident record of fossil Stolotermitidae and extends the fossil record of the family back to the Early Miocene.It also is the first direct evidence of fossil Isoptera from New Zealand,though silicified termite faecal pellets,referable to Kalotermes brauni,have been previously described.S.kupe indicates that Stolotermitidae has been present in the Australasian region since at least the Early Miocene.     

Mineralogy of fossil resins in Northern Eurasia

The investigation is focused on identification and origin of fossil resins from the Cretaceous, Tertiary, and Quaternary sediments of Northern Eurasia on the basis of detailed study of their physical and chemical characteristics: morphology; size; mass; density; optical, mechanical, and thermal properties; chemical composition; etc. The composition of amorphous organic minerals with polymeric structure, fossil resins included, is studied with IR spectrometry, the EPR method, derivatography at low heating rates, XRD, chemical analysis, emission spectrometry, etc. The results of investigation summarized for the Baltic-Dnieper, North Siberian, and Far East amber-bearing provinces show some similarity of fossil resins in combination with specific features inherent to each province. Resins from the Baltic-Dnieper province should be termed as amber (succinite). Their variety is the most characteristic of Northern and Eastern Europe. Amber-like fossil resins from the North Siberian and Far East provinces are irrelevant to succinite. They usually occur as brittle resins, namely, retinite and gedanite, without jewelry value. Viscous fossil resin rumänite with an expected high economic value occurs in the Far East, on the shore of Sakhalin Island.     

Conifer fossil woods from the Santa Marta Formation (Upper Cretaceous), Brandy Bay,James Ross Island,Antarctica

Conifer fossil woods from the Santonian to lower Campanian Santa Marta Formation are anatomically studied in detail. The wood flora is dominated by conifers, mainly Araucariaceae. Conifer fossil woods represent 84% of the samples (26 of 31) of the assemblage. The remaining samples are dicotyledon woods which are not included in this study. Woods are mostly calcified and preservation is often excellent. Fossil woods include three species of Agathoxylon, Phyllocladoxylon antarcticum, Cupressinoxylon hallei and a new species of Cupressinoxylon, C. rotundum Pujana sp. nov. The conifer-dominated forests are consistent with the pollen and macrofloras previously described from sediments of the same stratigraphic unit. This fossil wood assemblage contributes to understand the floristic changes that took place in the Cretaceous forests.